1. Field of the Invention
The present invention relates to a cutting apparatus for cutting workpieces such as plates made from woods, resins, rubbers, or various fibers into specific widths.
2. Description of the Related Art
In the wood working industry including manufacture of residences, buildings, interiors, furniture, and the like, much of plates such as plywoods are used. Plates such as plywoods used for these applications are cut into predetermined dimensions, to be machined into shapes optimum to the applications. Saws such as circular saws or band saws are used to cut plates into specific dimensions. Apparatuses for cutting plates into specific dimensions with a saw are commercially available. A typical one of these apparatuses includes a supply mechanism for supplying a plate to a saw while holding both surfaces of the plate between rollers, a cutting mechanism disposed in a pathway of the plate supplied by the supply mechanism and having a circular saw for cutting the plate into specific widths, and a discharge mechanism for discharging the plate which has been already cut by the cutting mechanism.
The cutting apparatus having the above-described structure, however, has a disadvantage that since a large amount of chips, caused at the time of cutting a plate with a saw, are discarded by incineration or the like, an additional cost for discarding the chips must be taken into account. Another disadvantage is that since a saw blade has sets projecting from the saw teeth alternately in the opposite directions, the overall thickness of the saw includes the thickness of the sets in addition to the thickness of the saw blade, and accordingly, at the time of cutting a plate, a plate portion having a thickness of 3 to 5 mm is lost as cut chips, with a result that the plate cannot be cut in a state being overall effectively utilized. From the above description, it is apparent that the utilization efficiency of a plate becomes lower as the cutting width of the plate becomes finer. Now, it is assumed that when a plate is cut into a width of 50 mm with a saw, a plate portion having a width of 5 mm is lost. This means that about 10% of the plate cannot be effectively utilized due to the loss caused by cutting.
The apparatus for cutting plates with a saw has a further disadvantage that a noise level becomes significantly large, and more specifically, reaches 85 dB in the vicinity of the apparatus. The cutting apparatus of such a large noise level has a great difficulty in damping the noise, and therefore, has a large limitation in an installation environment of a factory containing the apparatus. The sawing apparatus has still a further disadvantage that it is difficult to obtain a smooth cut surface of a plate. This is because cutting marks caused by cutting with a large number of saw teeth remain on the cut surface of the plate. Accordingly, if pieces cut from a plate are used for an application requiring plate products each having a smoothly finished cut surface, the cut surface of each of the pieces must be smoothly cut by a plane or the like, or polished by a sheet of sand paper or the like, thereby giving rise to a problem that it takes a lot of time to finish the pieces cut from the plate.
A cutting apparatus improved to solve the above-described disadvantages of the apparatus of cutting plates with a saw has been proposed in Japanese Patent No. 2873224. The cutting apparatus for cutting plates, disclosed in this document, is configured to forcibly transfer a plate by a plate supply mechanism and a plate discharge mechanism, and cut the plate by making the plate pass through a plate cutting mechanism having a pair of upper and lower fixed cutter blades. The above cutting apparatus for cutting plates with the pair of upper and lower cutter blades can solve many of the disadvantages of the above-described apparatus for cutting plates with a saw. The cutting apparatus for cutting plates disclosed in the above patent, however, has a problem that since a plate is cut by forcibly pushing the plate to the fixed cutter blades of the cutting mechanism with the aid of a plate supply force given by the supply mechanism, a cutting ability is limited, and more specifically, a relatively thick plate cannot be cut.
An object of the present invention is to provide a cutting apparatus capable of efficiently cutting a workpiece such as a plate at a low noise level while reducing the occurrence of cut chips.
In accordance with an aspect of the present invention, there is provided a cutting apparatus including a first annular member having a center eccentric from an axis of a rotating shaft and fixed to the rotating shaft, a bearing having an inner race and an outer race, the inner race being fixed to the first annular member, a disk cutter fixed relative to the outer race of the bearing and a balancer fixed to the rotating shaft in a state being eccentric in the direction opposite to the eccentric direction of the first annular member.
Preferably, a second annular member is fixed to the outer race of the bearing, and the disk cutter is fixed to the second annular member. Preferably, at least a pair of cutter guides are disposed on both sides of the disk cutter. The cutting apparatus may further include a workpiece carrying mechanism for carrying a workpiece and a one-way rotating mechanism selectively engageable with either the disk cutter or the second annular member.
The rotating shaft may be rotated in the direction opposite to the carrying direction of the workpiece. The one-way rotating mechanism may be configured to prohibit the rotation of the disk cutter at the time of idling. With this configuration, the disk cutter is prevented from being rotated at a high speed together with the rotating shaft at the time of idling, to thereby ensure safety of an operator. At the time of cutting a workpiece, a workpiece carrying force is applied to the disk cutter to slowly rotate the disk cutter in the same direction as the workpiece carrying direction. Preferably, a distance between the center of the first annular member and the axis of the rotating shaft is in a range of 0.3 mm to 2.0 mm.
In accordance with another aspect of the present invention, there is provided an annular member having a center eccentric from an axis of a rotating shaft and fixed to the rotating shaft, a bearing fixed to the annular member and a disk cutter fixed relative to the bearing wherein the annular member is balanced in weight such that a center of gravity of a rotator including the annular member, the bearing, and the disk cutter coincides with the axis of the rotating shaft.
In accordance with a further aspect of the present invention, there is provided a workpiece carrying mechanism for carrying a workpiece, a first cutter assembly for partially cutting a workpiece carried by the workpiece carrying mechanism, the first cutter assembly being disposed on the upper side of the workpiece and a second cutter assembly for partially cutting a workpiece carried by the workpiece carrying mechanism, the second cutter assembly being disposed on the lower side of the workpiece wherein each of the first and second cutter assemblies includes a first annular member having a center eccentric from an axis of a rotating shaft and fixed to the rotating shaft, a bearing having an inner race and an outer race, the inner race being fixed to the first annular member, a disk cutter fixed relative to the outer race of the bearing and a balancer fixed to the rotating shaft in a state being eccentric in the direction opposite to the eccentric direction of the first annular member.
Preferably, the cutting apparatus further includes a synchronizing mechanism for rotating the rotating shaft of the first cutter assembly and the rotating shaft of the second cutter assembly in synchronization with each other. The eccentric direction of the center of the first annular member of the first cutter assembly from the axis of the rotating shaft may be opposite to the eccentric direction of the center of the first annular member of the second cutter assembly from the axis of the rotating shaft. With this configuration, the disk cutter of the first cutter assembly and the disk cutter of the second cutter assembly are idled with phases thereof being offset from each other by 180 degrees, with a result that it is possible to reduce vibration and noise.
Alternatively, the eccentric direction of the center of the first annular member of the first cutter assembly from the axis of the rotating shaft may be the same as the eccentric direction of the center of the first annular member of the second cutter assembly from the axis of the rotating shaft. With this configuration, the disk cutter of the first cutter assembly and the disk cutter of the second cutter assembly are idled with phases thereof being identical to each other, with a result that it is possible to reduce noise.
The above and other objects, features and advantages of the present invention and the manner of realizing them will becomes more apparent, and the invention itself will best be understood from a study of the following description and appended claims with reference to the attached drawings showing some preferred embodiments of the invention.